I wonder why arguing in comments is not allowed on this Stack Exchange website.

Example: I was reading the answer https://health.stackexchange.com/a/4332/43 and saw:

[![enter image description here][1]][1]

since all comments got deleted, I can't see which points of the answer might be questionable.

Believing that answer is incorrect isn't always enough to write a new answer. And using the chat isn't so convenient for the future readers of the answer. 

On other Stack Exchange websites, it's common to argue in comments.


  [1]: https://i.sstatic.net/MSIAg.png